Common use of S-3 Registration Statement Clause in Contracts

S-3 Registration Statement. MarkWest may, at any time it is eligible to do so, or shall, if eligible, upon the written request of the Holders of at least 50% of the Registrable Securities originally issued pursuant to the Purchase Agreement, file a shelf registration statement on Form S-3 for the resale of any then existing Registrable Securities or, if permitted by the Commission, file a post-effective amendment on Form S-3 to the Shelf Registration Statement on Form S-1 (the “S-3 Shelf Registration Statement”). Upon the effectiveness of the S-3 Shelf Registration Statement, MarkWest shall no longer be required to keep effective the Shelf Registration Statement and all references to the Shelf Registration Statement in this Agreement shall then automatically be deemed to be a reference to the S-3 Shelf Registration Statement.